Apparatus for the in-place destruction of filed documents

ABSTRACT

An air manifold is mounted in a file cabinet and provided with air-jet orifices arranged to direct air jets onto the bottom edge region of file folders stored in the cabinet. Means, such as a squib-activated oxidizer sheet, also are mounted in the cabinet in position to ignite the bottom edges of the folder. The system as a whole operates as a gravity-feed furnace by injecting the high velocity air jets at the bottom of the burning files and, as the bottom surfaces are consumed, the file contents fall into the region of rapid combustion.

United States Patent 1 91 Matthews 1 51 May 1,1973

APPARATUS FOR THE lN-PLACE DESTRUCTION OF FILED DOCUMENTS [75] Inventor: Donald R. Matthews, San Jose,

Calif.

[73] Assignee: The United States of America as represented by the Secretary of the Navy [22] Filed: June 15, 1972 [21] Appl. No.: 263,052

52 US. Cl ..109/29, 109/24, 110/18 R 511 1111. c1 ..EOSg 3/00 [58] Field of Search ..109/24,25,23,33,

[56] References Cited UNITED STATES PATENTS 3,448,702 6/1969 McLouth ..1 10/18 R 3,431,873 3/1969 Durand ....110/18 R 3,638,591 2/1972 Lausmann ....1 10/18 R 3,650,226 3/1972 Conroy et a] ..l09/25 Primary Examiner-Dennis L. Taylor Att0meyRichard S. Sciascia et a1.

[57] ABSTRACT An air manifold is mounted in a file cabinet and provided with air-jet orifices arranged to direct air jets onto the bottom edge region of file folders stored in the cabinet. Means, such as a squib-activated oxidizer sheet, also are mounted in the cabinet in position to ignite the bottom edges of the folder. The system as a whole operates as a gravity-feed furnace by injecting the high velocity air jets at the bottom of the burning files and, as the bottom surfaces are consumed, the file contents fall into the region of rapid combustion.

6 Claims, 5 Drawing Figures Patented May 1, 1973 2 Sheets-Sheet 1 Patented May 1, 1973 3,730,111

2 Sheets-Sheet 23 APPARATUS FOR THE IN-PLACE DESTRUCTION OF FILED DOCUMENTS BACKGROUND OF THE INVENTION The present invention relates to systems for destroying filed documents and other papers and, in particular, to systems for destroying these papers in-place within the file cabinets.

Classified documents and other materials vital to the security of the country frequently must be taken into hostile territories or waters where there is a constant danger of compromise if their contents become known. Obviously, some means must be provided to assure complete and rapid destruction and, in providing these means it must be assumed that there may be insufficient time or personnel to physically remove the documents from a file and place them in a suitable furnace. Consequently, the documents must be destroyed inplace or, in other words, in their stored disposition within the file cabinet. Although there have been a number of proposals directed toward this problem, it appears that, for one reason or another, these proposals have attendant disadvantages which tend to discourage their widespread use. For example, the size, weight and volume of file cabinets frequently is at a premium and destruct systems which unduly increase these factors are undesirable. Also, due to the large number of cabinets in use, the expense of the structure becomes a very significant factor. Further, since in-place destruction contemplates the use of a tile cabinet as a furnace, safety considerations become significant and it also is important to assure that the destruction of file contents does not itself destroy the entire file cabinet.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a file cabinet capable of quickly and thoroughly destroying its contents in-place within the cabinet.

Another object is to provide such a cabinet in a relatively inexpensive and simple manner.

Yet another object is to assure that the destruction within the cabinet is accomplished in a safe and efficient manner.

Still another object is to assure that the destruction of the contents of the cabinet does not itself destroy the cabinet.

These and other objects which will become apparent can be accomplished by utilizing a gravity-feed blast furnace principle employingan air manifold having closely spaced air jet orifices directed at the bottom edges of the file folders to burn away the region around these bottom edges and permit the file contents to drop downwardly into a zone of rapid combustion. Air jet control can provide optimum destruct cycles by maintaining an optimum surface mass flux and, when such controls are exercised, the combustible destruction of the contents can be accomplished at a relatively low temperature that does not destroy the file drawers and other cabinet hardware. Preferably, the cabinet also mounts an igniter means to initially ignite the bottom edges of the file folders and, most suitably, such an igniter is provided by a sheet-like, squib-activated oxidizer.

BRIEF DESCRIPTION OF THE DRAWING The invention is illustrated in the accompanying drawings of which:

FIG. 1 is a perspective view of a file cabinet showing one embodiment of the air-jet system of the present invention;

FIG. 2 is a somewhat diagrammatic sectional view of one of the file drawers of the FIG. 1 embodiment;

FIG. 3 is another somewhat diagrammatic perspective view of a file drawer illustrating an alternative embodiment of the air-jet system;

FIG. 4 is a view similar to FIG. 2 showing a drawer of the FIG. 3 embodiment and its associated air-jet system, and

FIG. 5 is an enlarged perspective of a section of the FIG. 4 drawer.

DETAILED DESCRIPTION OF THE INVENTION The air-jet system of the present invention can be readily built into standard file cabinets, such as cabinet 1 shown in FIG. 1 which has the usual vertical stack of drawers 2 slideably mounted in various well-known manners in the cabinet. For purposes of description, the cabinet can be considered as having front and rear walls 3 and 4 as well as side walls 6 and 7 while drawers 2 also have front and rear walls 8 and 9 as well as side walls 11 and 12. Customarily, cabinets of this type are formed of steel plate the thickness of which varies with the particular use for which the cabinet is designed. For example, cabinets of the type intended to store classified documents or other valuable papers may have their exterior walls formed of a rather thick and strong steel plate, such as 96 inch plate. Other conventional cabinets designed for normal storage purposes may have a wall thickness of about 26 gage.

As shown in FIG. 1, each of the drawers is adapted to contain a plurality of closely-packed file folders 13 which are conventional V-shaped folders having a closed bottom edge 14 that retains the file contents when the folders are in the illustrated upright position. Other filing arrangements of course are contemplated such, for example, as the use of hanging-type folders which will be described with reference to FIGS. 3 and 4. The principal concern of the present invention is that these folders be formed of a combustible material and that they be of a top-loading type having a closed bottom edge, such as edge 14 to retain material when the folder is in its file disposition.

One of the features of the present invention is the use of an air-manifold system generally designated by the numeral 16 which, within certain functional limits, can be installed in the cabinet in a variety of manners. As shown in FIG. 1, this manifold system includes a horizontal U-shaped section having side or leg portions 17 and 18 coupled by a base portion 19 provided centrally with a fitting 21 by means of which the manifold can be coupled to a pressurized air supply. Thus, for example, the manifold can be coupled to the source by a conduit 22 controlled by a valve 23 which is adjustable through knob 24 to control the amount of air passing into the conduit. The on and off positions of valve 23, in turn, can be electrically controlled in any desired manner such, as for example, a starter switch 26.

The horizontal, U-shaped section of air manifold system 16 is supportably mounted in a fixed position on the bottom of the cabinet and, as shown in FIG. 1, the manifold also includes a plurality of vertical riser sections or conduits 27 communicated at their bottom portions with the horizontal section of the manifold and extending upwardly from the horizontal section to a point at or near the top of the cabinet. Preferably, these risers are provided at about a l.5 inch spacing along each side or leg 17 and 18 of the horizontal portion of the manifold. The purpose of the risers is to inject a plurality of air jets at the bottom portion of the file folders stored in each of the cabinet drawers, the air jets or blasts being intended to promote the combustion of the folders and their contents. For this purpose, each of the risers 27 is formed with vertically spaced air-jet orifices 28, the spacing of these orifices coinciding with the bottom region of the file folders contained in each of the drawers. Further, to permit the air jets to impinge directly onto the bottom regions of the folders, the drawers themselves are provided with openings 29 aligned with the air jet orifices.

When a need arises for the rapid destruction of the file contents, this destruction readily can be accomplished by igniting the bottom region of the file folders. As the combustion of the bottom edge portions 14 proceeds, the file contents drop or fall by gravity into the region of rapid combustion where they are thoroughly and quickly consumed. The system thus operates a gravity feed blast furnace by injecting high velocity air at the bottom of the burning file folders.

The manner in which the bottom edges of the folders initially are ignited is somewhat a matter of choice and, if desired, the manifold can be employed as an air-fuel line although this expedient presently appears expensive and perhaps not as effective as could be desired. A preferred ignition system is provided by a plurality of igniter sheets or bars 31 which, as indicated in FIGS. 1 and 2 extend longitudinally along the bottom of each drawer directly beneath the file folders so as to produce the initial ignition at several spaced points along the bottom of the folders. As contemplated these igniters are rectangular bars formed of a mixed and cast oxidizer material such as ammonia perchlorate and powdered aluminum, the resulting substance being a solid, somewhat flexible material which, if desired, can be contained in suitable insulated trays. Igniters of this type commonly are used in missile or rocket systems, as well as a number of other similar applications and, as may be known, their ignition is accomplished by a suitable firing squib 32 which, when electrically ignited, produce a flame to ignite the oxidizer bars. In the illustrated arrangement, firing squib 32 is electrically energized in response to the closing of the starter switch 26 so that the ignition of the bottom edges of the folders is concurrent with the establishment of the air jets. As a safety measure and also to remove the products of the resulting combustion, cabinet 1 can be provided with a vent or flue 33.

The embodiment of the invention illustrated in FIGS. 3 and 4 is similar in principal and operation to that which already has been described. It differs primarily in that a separate air manifold system 16 is provided for each of cabinet drawers 2. Thus, instead of having a single horizontal section with vertical risers, the FIG. 3

and 4 embodiment has a single, horizontal, U-shaped section 33 mounted on the bottom portion of each of the drawers, this horizontal section also having legs or sides 34 and 35 and a base 36. As will be noted, base 36 is adapted to be coupled to an air source by a flexible conduit 37, the flexibility of this conduit being required since the drawers customarily are slideably mounted in the cabinet. Horizontal legs 34 and 35 each are provided with spaced air-jet orifices 38 and, as will be appreciated, these orifices are disposed to direct jets of air at the bottom edge region of the file folders. In this regard, however, it should be noted that the embodiment of FIGS. 3 and 4 contemplate the use of a hanging-type of folder 39 which again are V-shaped with a closed bottom edge 41, the difference being that each of the legs of the V are supported on separate horizontal rods 42 which, in turn, are slideably supported on longitudinal horizontal rods 43 journaled in the end walls of each drawer. This type of folder is best known as the Pendaflex folder, commonly used in many filing systems. Obviously, other types of folders also permit the accomplishment of the purposes of the present invention providing the folders are formed of a combustible material and have enclosed bottom edge. The hanging folders are advantageous in that these folders are supported with their bottom edges spaced a distance from the bottom of the drawer so that added space is provided for the contents of the file to drop when the bottom edge region of the folders is burnt away. Ignition for the folders of the embodiment of FIGS. 3 and 4 can be accomplished in the same manner as has already been described with reference to FIGS. 1 and 2.

The operation of the present system should be readily apparent from the foregoing description. As stated, the system essentially is a gravity feed blast furnace utilizing the high velocity air jets to promote rapid and thorough combustion of the file contents. The use of the gravity feed of the contents into the region of rapid combustion is highly advantageous since, for one reason, it achieves a high linear regression rate that essentially eliminates excessive thermal soak and charring. These factors, in turn, result in a significantly lower heat load on the cabinet as well as the area surrounding the cabinet so as to prevent possible destruction of the cabinet by overheating and also to minimize the fire hazard produced by the combustion. As will be appreciated, the lower heat load on the cabinet results because of the low ignition temperature of the combustible file contents as compared to the ignition temperature of charred material. In this regard, when a heat wave moves faster than a flame front the result is that the heat wave produces a char which in turn requires a higher ignition temperature for combustion. External cooling may be found desirable for use with some cabinets such as those formed of relatively thick steel plate which traps rather than radiates the interior heat. On the other hand, the destruct method readily can be adapted to existing file cabinets constructed of relatively thin gage steel since the interior heat appears to be effectively radiated by the walls of these cabinets. Obviously, excessive interior heat caused by trapping or by low rate destruction is capable of producing high heat loads on the cabinet that may result in destruction of the cabinet itself along with its contents.

Another distinct advantage of the present system is that the jet velocity can be controlled to provide optimum destruct cycles which, in turn, may depend upon the density of the drawer loading. Using the present arrangement, a drawer loading of 50 pounds of paper has been destroyed within minutes without destruction of the drawer or cabinet. Further, using the FIG. 3 and 4 embodiment, it is possible to achieve partial file destruction by the use of selective burning in one or more of the drawers. In general, the system provides an inexpensive and simple manner of very quickly destroying classified documents as the occasion may arise.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim: 1. Filing cabinet apparatus adapted for burnably destroying the contents of file folders stored in an upright closely-packed disposition extending lengthwise of the cabinet, said folders being formed of a combustible material and having closed bottom edges for retaining the contents when in said upright position, the apparatus comprising:

an air manifold mounted in the cabinet and provided with a plurality of air-jet orifices for directing air jets directly at the bottom edge region of the stored folders at spaced intervals along the length of the cabinet,

ignition means carried by the cabinet for initiating combustion selectively along said bottom edge region, and

means adapted to communicate said manifold with a source of pressurized air,

whereby said bottom edge region can be ignited and the resulting combustion fanned by said air jets to promote rapid combustion at a relatively low temperature, said combustion burning away said bottom edges to permit said file folder contents to drop and be destroyed in the region of rapid combustion.

2. The apparatus of claim 1 wherein said cabinet is formed with at least one file drawer extending lengthwise of the cabinet,

said manifold being mounted in the bottom portion of said drawer and extending horizontally from the front to the rear portion of the drawer along each of its sides,

said jet orifices being closely spaced along each of said horizontal extents.

3. The apparatus of claim 1 wherein said cabinet is formed with at least one file drawer and said file folders are of a top-loading type adapted to be suspendably hung in said closely-packed disposition in said drawer,

said cabinet apparatus further including means carried by said drawer for suspendably hanging said folders with their bottom edges spaced a fixed distance from the bottom of the drawer whereby when said bottom edge region of the folders is burned-away said filed contents can drop into said space.

4. The apparatus of claim 3 wherein:

said manifold is mounted in the bottom portion of said drawer and extends horizontally from the front to the rear portion of the drawer along each of its sides, and

said jet orifices are provided at closely-spaced intervals along each of said horizontal extents.

5. The apparatus of claim 1 wherein said cabinet is formed with a plurality of vertically-stacked file folder drawers extending lengthwise of the cabinet and said manifold includes:

a plurality of pipe sections disposed at closely-spaced intervals along each side of each drawer, said sections being mounted in the cabinet externally of i the drawers and extending vertically from the cabinet bottom at least to the bottom of the topdrawer of the stack,

said pipe sections being closed at the top and being provided with vertically-spaced air-jet orifices arranged to direct air jets into the bottom edges of said file folders, and

said drawers each being provided with openings aligned with said spaced orifices to expose said bottom edges to said air jets.

6. The apparatus of claim 5 wherein:

said file folders are of a top-loading type adapted to be suspendably hung in said closely-packed disposition in said drawers, and

said cabinet apparatus further includes:

means carried by each drawer for suspendably hanging said folders with their bottom edges spaced a fixed distance from the bottom of the drawer. 

1. Filing cabinet apparatus adapted for burnably destroying the contents of file folders stored in an upright closely-packed disposition extending lengthwise of the cabinet, said folders being formed of a combustible material and having closed bottom edges for retaining the contents when in said upright position, the apparatus comprising: an air manifold mounted in the cabinet and provided with a plurality of air-jet orifices for directing air jets directly at the bottom edge region of the stored folders at spaced intervals along the length of the cabinet, ignition means carried by the cabinet for initiating combustion selectively along said bottom edge region, and means adapted to communicate said manifold with a source of prEssurized air, whereby said bottom edge region can be ignited and the resulting combustion fanned by said air jets to promote rapid combustion at a relatively low temperature, said combustion burning away said bottom edges to permit said file folder contents to drop and be destroyed in the region of rapid combustion.
 2. The apparatus of claim 1 wherein said cabinet is formed with at least one file drawer extending lengthwise of the cabinet, said manifold being mounted in the bottom portion of said drawer and extending horizontally from the front to the rear portion of the drawer along each of its sides, said jet orifices being closely spaced along each of said horizontal extents.
 3. The apparatus of claim 1 wherein said cabinet is formed with at least one file drawer and said file folders are of a top-loading type adapted to be suspendably hung in said closely-packed disposition in said drawer, said cabinet apparatus further including means carried by said drawer for suspendably hanging said folders with their bottom edges spaced a fixed distance from the bottom of the drawer whereby when said bottom edge region of the folders is burned-away said filed contents can drop into said space.
 4. The apparatus of claim 3 wherein: said manifold is mounted in the bottom portion of said drawer and extends horizontally from the front to the rear portion of the drawer along each of its sides, and said jet orifices are provided at closely-spaced intervals along each of said horizontal extents.
 5. The apparatus of claim 1 wherein said cabinet is formed with a plurality of vertically-stacked file folder drawers extending lengthwise of the cabinet and said manifold includes: a plurality of pipe sections disposed at closely-spaced intervals along each side of each drawer, said sections being mounted in the cabinet externally of the drawers and extending vertically from the cabinet bottom at least to the bottom of the top-drawer of the stack, said pipe sections being closed at the top and being provided with vertically-spaced air-jet orifices arranged to direct air jets into the bottom edges of said file folders, and said drawers each being provided with openings aligned with said spaced orifices to expose said bottom edges to said air jets.
 6. The apparatus of claim 5 wherein: said file folders are of a top-loading type adapted to be suspendably hung in said closely-packed disposition in said drawers, and said cabinet apparatus further includes: means carried by each drawer for suspendably hanging said folders with their bottom edges spaced a fixed distance from the bottom of the drawer. 